This continuing project involves the development of an isolation procedure, the chemical characterization, and pharmacological evaluation of cardiotonic agents found in sea anemones. Currently, the work is concentrating on three different agents found in two different species of the genus anthopleura. One is a polypeptide, the second a protein, and the third has not yet been isolated in analytical purity. Separations involve several chromatographic techniques. Assays for purity are several different electrophoresis methods and amino acid analyses as well as bioassays for positive inotropic effect. The pharmacological studies are being focused currently on Ca ions uptake, influx, and efflux; Ca ions binding; relationship between external Ca ions and K ion concentration on the cardiotonic effect of the polypeptide. The other two agents will be examined for: involvement of adrenergic mechanism; a study of anti-arrhythmic action; effects of the new agents on blood pressure, cardiotonic effect, EKG and heart rate. BIBLIOGRAPHIC REFERENCES: T.R. Norton, S. Shibata, M. Kashiwagi, and J. Bentley, "The Isolation and Characterization of the Cardiotonic Polypeptide, Anthopleurin-A from the Sea Anemone Anthopleura xanthogrammica", submitted to J. Pharm. Sci., Feb., 1975. S. Shibata, T.R. Norton, T. Izumi, T. Matsuo, and S. Katsuki, "Polypeptide (AP-A) from Sea Anemone (Anthopleura xanthogrammica) with Potent Cardiotonic Action", to be presented at 1975 Fall meeting of Amer. Soc. for Pharmacol. and Exp. Ther. and appear (abstract) in the Fall 1975 issue of the Pharmacologist.